A practical reference on neurotrophic factor: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-06-11 and is reviewed periodically as new material appears.
当时的短肽研究普遍关注能否穿越血脑屏障、在低剂量下产生中枢效应，Semax 属于这一路线。鼻内给药是其主要使用方式，俄语文献报道的适应症涵盖缺血性卒中、短暂性脑缺血发作、认知功能减退以及视神经病变。这些研究大多发表在当地期刊上，样本规模与终点设置同西方试验惯例存在差异，国际同行对其临床证据的强度看法不一。
各国监管态度分化明显。俄罗斯按处方药管理，部分东欧国家留有使用记录；欧盟与美国未批准其作为药物上市，市面流通品通常标注为研究用化学品。身份差异意味着标示含量、纯度与无菌性缺少统一核查。体育领域还牵涉反兴奋剂名录，跨境携带则受目的地药品法规约束。
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its chain combines the first seven residues of corticotropin with a C-terminal proline-glycine-proline extension, a modification intended to slow enzymatic breakdown. The free peptide has a molecular mass near 813.9 daltons. It belongs to the class of ACTH-derived fragments studied for central nervous system activity rather than for adrenal steroid stimulation. This structural relationship to a natural hormone fragment is the usual starting point for describing the compound in the literature.
Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.
Laboratory work points toward modulation of neurotrophic signaling, particularly expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal tissue. Studies also describe effects on monoamine turnover, inflammatory mediators, and oxidative markers. These observations come mainly from animal models and cultured cells, so the causal chain in humans is not firmly established. Whether the reported molecular changes translate into measurable clinical benefit is an open question. Reviews generally present the mechanism as plausible rather than demonstrated.
| Property | Value | Notes |
|---|---|---|
| 结构类别 | 线性合成七肽 | 无环化结构，不含二硫键 |
| 氨基酸序列 | Met-Glu-His-Phe-Pro-Gly-Pro | N 端为甲硫氨酸 |
| 分子量 | 约 814 Da | 游离碱形式的计算值 |
| 外观 | 白色至类白色粉末 | 具吸湿性 |
| 溶解性 | 易溶于水 | 亦可溶于甲醇等极性溶剂 |
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. It was developed as a fragment analog of adrenocorticotropic hormone, modeled specifically on the ACTH(4-10) region. The first four residues reproduce that fragment, while a Pro-Gly-Pro tripeptide is appended at the C-terminus. Work on the compound originated in Russia, where it entered clinical use as an intranasal preparation. Its sequence places it among short regulatory peptides studied for effects on the central nervous system rather than on the adrenal axis.
The C-terminal Pro-Gly-Pro extension is not incidental. Proline-rich tails are known to resist several common peptidases, and the published literature attributes the longer half-life of Semax, relative to unmodified ACTH fragments, to this feature. The modification also removes the melanocyte-stimulating and corticosteroidogenic activity that characterizes longer ACTH-derived sequences. Because the molecule is small and hydrophilic, it is typically formulated as an aqueous solution for intranasal or parenteral delivery. Acetylation or amidation at the termini appears in closely related research peptides and shifts the mass by a fixed increment.
Reported pharmacological work centers on neurotrophic signaling, including changes in BDNF and NGF expression in hippocampal tissue in animal models. Human data come largely from studies conducted in Russia, and how well those results generalize to other populations remains an open question. Regulatory status differs sharply by jurisdiction: Semax is a registered prescription medicine in Russia, while it holds no approved marketing status in the United States or the European Union. Outside such jurisdictions it is generally handled as a research chemical, which affects both documentation and quality expectations.
Regular lorazepam use during late pregnancy (the third trimester), carries a definite risk of benzodiazepine withdrawal syndrome in the neonate. Neonatal benzodiazepine withdrawal may include hypotonia, reluctance to suck, apneic spells, cyanosis, and impaired metabolic responses to cold stress. Symptoms of floppy infant syndrome and neonatal benzodiazepine withdrawal syndrome have been reported to persist from hours to months after birth. Lorazepam may also inhibit fetal liver bilirubin glucuronidation, leading to neonatal jaundice. Lorazepam is present in breast milk, so caution is exercised about lorazepam usage for breastfeeding patients.
==== Enantiomeric excesses observed in extraterrestrial amino acids ==== More recently, amino acids from several carbonaceous chondrites have been identified with significant L-enantiomeric excesses. L-excesses from 3–15% in several non-protein α-dialkyl amino acids have been found in the Murchison and Murray meteorites. Their extraterrestrial origin is indicated by their absence in biological systems and significant heavy isotope enrichments in 13C and deuterium compared to terrestrial values. Further characterisation of L-isovaline excesses up to 20.5% in a range of carbonaceous chondrite groups have supported a hypothesis that increasing hydrothermal alteration of the host meteorite correlates with increasing observed L-enantiomeric excess. Large L-excesses for α-H amino acids have also been reported, but these are more problematic due to the potential for terrestrial contamination. The ungrouped C2 chondrite Tagish Lake has L-aspartic acid excesses up to ~60%, with carbon isotope measurements indicating an extraterrestrial origin due to significant enrichments in 13C. In Tagish Lake, proteinogenic amino acids show both significant L-excesses, and racemic mixtures: glutamic acid, serine, and threonine were found to have ~50 – 99% L-excesses, while alanine was racemic. It has been proposed that extraterrestrial amino acid L-excesses observed in carbonaceous chondrites are a result of differences in the crystallisation behaviour of the enantiomers.
=== Local Intelligence Unit === Post 2014 Burdwan blast, which unearthed Bangladesh-based militant group Jamaat-ul-Mujahideen Bangladesh, middle-east's terrorist group Islamic State and Pakistan's Inter-Services Intelligence terror module, the need for strengthening the local intelligence gathering mechanism was first felt. Following the incident the state govt has set up a new intelligence agency to counter terrorism, bust terror modules and invigilate suspicious movements in West Bengal and also to foil militant infiltration into the state.
Sources: en.wikipedia.org
=== 1999–2003: The Double Duo, The ConstruKction of Light and The Power to Believe === King Crimson reconvened in 1999. With Levin busy with session work, and believing Bruford to be more concerned with his jazz band Earthworks than Crimson, Fripp decided the next phase of King Crimson would be a "Double Duo" of himself, Belew, Gunn, and Mastelotto. This line-up recorded The ConstruKction of Light at Belew's home studio in Mount Juliet, Tennessee. Fripp was inspired by Tool's album Undertow during the writing process of The ConstruKction of Light. Released in May 2000, the album reached No. 129 in the UK. Most of the pieces were metallic, harsh and industrial metal–influenced, featuring Mastelotto performing exclusively on electronic drums, Gunn taking over the bass role on Warr Guitar, and a different take on the interlocking guitars of the 1980s quartet. With the exception of an "industrial blues" sung by Belew through a voice changer (under the pseudonym of "Hooter J. Johnson"), the songs were dense and complex. The album also contained the fourth installment of "Larks' Tongues in Aspic". It received a negative reception for lacking new ideas. At the same time as recording The ConstruKction of Light, the band also recorded an album of improvised instrumentals, Heaven and Earth, released under the name ProjeKct X.
In 1907, American tea merchant Thomas Sullivan began distributing samples of his tea in small bags of silk with a drawstring. Consumers noticed they could simply leave the tea in the bag and reuse it with fresh tea. However, the potential of this distribution and packaging method would not be fully realised until later. During World War II, tea was rationed in the United Kingdom. In 1953, after rationing in the UK ended, Yorkshire-based tea manufacturer Tetley launched the tea bag in the UK, and it was an immediate success. The "pyramid tea bag" (or sachet), introduced by Lipton and PG Tips/Scottish Blend in 1996, attempts to address one of the connoisseurs' arguments against paper tea bags by way of its three-dimensional tetrahedron shape, which allows more room for tea leaves to expand while steeping. However, some types of pyramid tea bags have been criticised as being environmentally unfriendly, since their synthetic material is not as biodegradable as loose tea leaves and paper tea bags.
== Structure == NFE2L2 and other genes, such as NFE2, NFE2L1 and NFE2L3, encode basic leucine zipper (bZIP) transcription factors. They share highly conserved regions that are distinct from other bZIP families, such as JUN and FOS, although remaining regions have diverged considerably from each other. NRF2 is a basic leucine zipper (bZip) transcription factor with a Cap "n" Collar (CNC) structure. NRF2 possesses seven highly conserved domains called NRF2-ECH homology (Neh) domains. From the N-terminus to the C-terminus, they are:
Sources: en.wikipedia.org
For example, people with migraine are more likely to become anxious and depressed, but people with anxiety and depression also have a higher risk of becoming affected by migraine. The most frequently reported migraine trigger for women is hormonal variation, followed by stress for both women and men. Disrupted sleep, fasting, missing meals, dehydration, and sensory overstimulation are also commonly reported triggers. There is strong evidence that hormonal changes, stress, quality of sleep, and fasting are causally related to migraine attacks. These "catalyst triggers" may increase activity in the hypothalamus or trigeminal system of the brain until it exceeds the brain's migraine threshold. From puberty onwards, women experience migraine attacks more frequently and with greater severity than men, particularly for migraine without aura. The incidence of attacks of migraine without aura is strongly related to hormonal fluctuations in estrogen, both monthly and across a woman's lifespan. Keeping the body's internal environment stable and consistent appears to protect the brain's migraine sensitivity threshold, while disruption and stresses may make it more likely for the brain to go past its sensitivity threshold. Lifestyle changes that support stability, such as regular sleep, regular meals, and stress management, can help to prevent migraines. Whether a possible trigger is an actual cause or an early symptom, it may be possible to reduce discomfort by managing exposure to sensory stimuli such as smells, lights, sound, or touch.
=== Sexual effects === From the available evidence, it seems men who have been circumcised with the aid of a circumcision device experience unchanged or heightened sexual pleasure and satisfaction. There is some evidence such men also derive long time improvements in erectile function. The accumulated data show circumcision has no adverse physiological effect on sexual pleasure, function, desire, or fertility. There is some evidence that circumcision has no effect on pain with intercourse, premature ejaculation, intravaginal ejaculation latency time, erectile dysfunction, or difficulties with orgasm. There are popular misconceptions that circumcision benefits or adversely affects the sexual pleasure of the circumcised person. According to a 2014 review, the effect of circumcision on sexual partners' experiences is unclear as it has not been well studied. According to a policy statement by the Canadian Paediatric Society that was reaffirmed in 2021, "medical studies do not support circumcision as having an impact on sexual function or satisfaction for partners of circumcised individuals".
== Ductal cell physiology == While ductal cells are a minor type of cell in the adult pancreas, they have a critical function besides making the network that transfers enzymes from acini to the digestive tract. The primary function of pancreas ductal cells is to secrete a bicarbonate-rich, isotonic fluid. This fluid washes away the inactive form of digestive enzymes in the ductal system, neutralizes stomach acidity and mucins, and creates a pH environment necessary for the pancreas's normal function. Multiple factors affect the rate of bicarbonate secretion: species, cell location in the ductal system, secretory rate, etc. When stimulated, bicarbonate levels can get to 140mM. Due to this, there is a contrast in concentration between the outside and inside environment of ductal cells. The channels and ion transporters on ductal cells vary on the luminal and basolateral membrane, meaning there is functional polarization of the ductal cell. The largest network branches in this system contain goblet cells that interact with ductal cells, making up about 2% of this structure—these cells aid mucin assembly. Furthermore, unlike other exocrine glands, the pancreas does not have myoepithelial cells around the ducts. Ductal cells have a single cilium that is made up of nine peripheral doublets but does not have a central microtubule. This cilium is considered vital for perceiving flow in ducts.
Sources: en.wikipedia.org
不存在。它是依据 ACTH 的一段序列人工设计的分子，天然蛋白质中找不到与之完全相同的七肽。名称属于研究代号，而非天然物质名。
Semax 对应 ACTH 第 4 至第 10 位的片段，并在两端做了替换与延长，使其不再具备促肾上腺皮质激素的典型内分泌活性。这一改动同时改变了它在体内的稳定性与分布特征。
俄罗斯将其列为处方药物，需要医生开具处方。多数其他国家把它当作研究化合物，不能作为药品销售或宣称疗效。具体合法性取决于当地法规。
Semax is a synthetic seven-amino-acid peptide derived from a fragment of corticotropin. It is used in Russia as a nasal preparation, while elsewhere it is studied as a research compound. It is not approved as a medicine in most countries.